Micromagnetic analysis of the effect of intergranular exchange on thermal stability in magnetic recording. I. Two-dimensional isotropic longitudinal media

We describe micromagnetic simulations that examine the effect of intergranular exchange on thermal stability of dibit transitions in two-dimensional (2D) isotropic longitudinal media. We found that, by maintaining the constant M_rt, the writing coercivity and the average grain planar area, K_u ⟨V⟩ is reduced with increasing h_e. Increasing the intergranular exchange enhances thermal decay and yields a smaller signal-to-noise ratio (SNR) at 10⁹ s. However, if both K_u⟨V⟩ and M_rt are fixed, ⟨D⟩ increases slightly if the writing coercivity is held constant but decreases slightly at a fixed intrinsic loop closure field. For both cases, a smaller SNR is always found at a higher exchange initially and after ten years. Thus, for 2D isotropic longitudinal media, the intergranular exchange must be reduced to achieve a higher SNR at 10⁹ s